Preservation of food products



Patented Apr. 24, 1951 ATENT OFFICE 2,550,264 PRESERVATION OF FOOD PRODUCTS Lloyd B. Jensen, Chicago, Ill., and William A. Miller, Manhattan, Kans, assignors to Swift & Company, Chicago, 11]., a corporation of Illinois No Drawing. Application May 10, 1949,

Serial No.

GClaims. l The present invention relates to the preparation and use of an antibiotic substance, and more particularly to the preparation and use of an antimicrobial substance of plant origin.

2 The ground plant tissue was then placed in a flask and covered with acetone. The flask was held at room temperature for approximately 24 hours and shaken at intervals. The acetone layer eon- The invention contemplates the utilization of 5 taining the acetone-soluble constituents oi the an antibiotic substance naturally associated with plant was separated from the insoluble material the tissues of the plant fletalostemumpurpurewm by filtration, and the acetone was distilled oil? (Vent. Rydb.), commonly called purple prairie under vacuum at 42 "C. The residue was taken clover. up in ethyl alcohol (95 per cent) so that 1 ml.

An object of the present invention is to proof the alcoholic extract contained the acetonev'ide a potent antibiotic substance of plant origin. soluble material in 3 grams of the original plant A further object of the invention is to provide tissue. an antibiotic substance which is nontoxic to hu- In order to evaluate the effectiveness of the anmans. tibiotic material in the alcohol solution obtained An additional object of the invention is to proin accordance with the example, the following vide an antibiotic substance which is relatively test was performed: heat stable. Serial dilutions of the extract were made in 10 Another object of the invention is to employ cc. broth tubes and the tubes inoculated with an antibiotic substance having an origin in a bacteria. Each 10 m1. broth tube contained about vegetative plant as an effective preservative for 75,000 cells of a food poisoning strain or Staphylofood products. 'coccus aureus, Bacillus nige'r, Clostridium spore- In achieving the objects of the present invengenes, Achnomobacter perozens, Salmonella typhition, the finely cut or ground prairie clover plant murium, and Psewdomot'za fluo'rescens. The tubes is treated with a suitable nona-queous, organic were allow-ed to incubate at a temperature of 37 solvent, such as acetone. The acetone layer con- C. and were inspected for bacterial growth at the taining the constituents of the plant tissue soluend of 2, 3, 6, and 7 days. In Table I are tabuble therein is separated from the acetone-insolulated the results obtained withjthe aforesaid bacble fibrous mass, the acetone removed therefrom, teria. The minus signs in said table indicate no and the extract taken up in a carrier solvent, bacterial growth, and the positive signs indicate such as ethanol. the presence of viable bacteria at the incubation The following example illustrates the preferred periods specified.

Table I Incuba- Salmonella Achro. S. Dilution 52a as. flier fi as? Controls 20 hrs. l

I g I I I I 7 2 500 I I I 7 2 ,000 Z I l I 7 g 2,000 g i i 7 The prairie clover antibiotic shows marked activity against the gram positive bacteria Staphylococcus aureus and Bacillus nicer, although the data given in the above table indicate that the eiTects of the said antibiotic vary in potency when tested against different organisms. aureas and Bacillus niger in dilutions as high as 1 to 1000, and Clostridium sporogenes in dilutions as high as l to 100. The bactericidal properties of the extract, lethally effective in the dilutions indicated for the various organisms, were demonstrated by inoculating nutrient agar plates with 0.1 cc. of the aforesaid dilutions which had been allowed to incubate for five days. After five clays incubation of the inoculated plates, no viable bacteria were observed as a result of the transfers.

Although acetone is the preferred primary solvent, we have found that other nonaqueous organic solvents are suitable as the extracting solvent. For example, dioxane, ethyl acetate, methyl ethyl ketone, and ethanol may be used.

We have also found a water extraction of the antibiotic material to be ineffective as an antibiotic,- apparently because of the proteinaceous material dissolved therein.

The heat stability of the antibiotic material was determined by heating portions of the material to a temperature of 96-100 C. for 3 minutes and then inoculating with Staphylococcas aareas. After incubating the material at a temperature of approximately 75 F. for seven days, the lethal potency was 1:200.

It is obvious that many variations in the solvent treating process may be advantageously employed. For example, since the antibiotic material isolated from the prairie clover plant is relatively heat stable, solvent temperatures may range from room temperature to boiling temperature of the solvent with consequent variations in extraction time. The higher the temperature, generally the less time is required for extraction. We have found it preferable to process the antibiotic substance contained in the clover plant by a two-stage solvent process involving first treating the substance with a primary solvent which is substantially removed, and then taking up the resulting extract with another solvent so as to form a solution which is a convenient form of using the product. We have found that acetone is a most effective primary solvent in producing the antibiotic substance from the plant tissue. After evaporating off the acetone, the preferred solution is made with a carrier solvent, such as ethanol, which may be consumed internally without harm. By using ethyl alcohol, we also utilize its well-known properties, such as iron-toxicity and ability to prevent contamina- In the processing of food products, a serious problem is the preservation thereof; and. although great strides have been made in improving the quality and keeping time of various food products by refrigeration, canning, curing, plant sanitation, etc., the problem of preservation of Thus, the extract kills Staphylococcus food requires the constant attention of the food 7 processor to improve long-established-methods of treating food and to devise new means of food control.

Food spoilage is due primarily to microbial action, and the species of microorganism respon-" sible for food deterioration are numerous. The sporing genera, Clostridium and Bacillus, for example, when contaminating food, cause food spoilage. Another serious concern of the food handler is food poisoning, which is often of an insidious nature because food products may be contaminated with one or more of the harmful bacteria referred to herein and yet appear 9 ganoleptically sound. Among the food poisoning bacteria, the most common food poisoner is Staphylococcus.

The antibacterial substance of the present invention may be used to retard or prevent microbial growth in various food products, all of which harbor pathogenic organisms in varying degrees. The antibiotic material disclosed herein, therefore, may advantageously be employed, for example, in treating meat products, such as hams, sausages, and canned meats; cream fillings for pastries, such as cream puffs, chocolate clairs, custards, and the like; and canned vegetables to prevent swelling due to organisms, such as the genus Bacillus.

The invention will be more fully understood from the following description of methods of using the antibiotic substance.

As hereinbefore mentioned, we have found that the antibiotic reagent herein described is lethal to a number of microbes in a 1 to 1000 dilution of the extract, the extract being of such strength that 1 ml. of the alcoholic solution thereof contained the acetone-soluble constituents in 3 grams of the plant. Therefore, the addition of 1 part of the solution to 1000 parts or less of the conventional pickling solution will result. in a meat product cured therewith which has a very marked increase in resistance to the development of pathogenic organisms.

The following is an example of a curing pickle stock, which may be used in a process for quickcuring hams when provided with antibiotic substance within the proportions outlined above; that is, the antibiotic substance may be added in an amount such as to effect a l to 500 dilution of the antibiotic material of the arbitrary strength herein described (1 ml.=3 g. of tissue).

To 100 gallons of a 90 Salo-meter solution there are added:

7 lbs. sodium nitrate 10 oz. sodium nitrite 20 lbs. sugar 378.5 cc. antibiotic solution Luncheon meat was cured according to conventional methods in which the antibiotic substance was present in a 1 to 500 dilution. The meat product was placed in six 6-pound cans and retorted to an inside temperature of 155 F. and incubated at 99 F. After 30 days of incubation, no swelling of the cans could be observed. The control cans swelled in one Week.

A further example of the utility of the said antibiotic material is the use in a cream filling for various pastries.

To determine the effectiveness, a standard cream filling used in clairs was inoculated with a bacterial solution containing 100,000 living Staphylococcus aureus 8-1 per 100 ml. and the filling incubated at a temperature between F. and F. The results of tests are given in Table II.

The foregoing tests indicate that the antibiotic preparation exerts a pronounced inhibiting action against the Staphylococcus aureus in cream fillings.

Obviously, many modifications and variations of the invention as hereinbefore set forth may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

We claim:

1. In the process of treating food products, the step of adding to a food product a small amount of an antibiotic substance derived from the plant Petalostemum-purpureum by treatment with a non-aqueous organic solvent to preserve said food product against pathogenic bacteria responsible for food poisoning and spoilage.

2. In the process .of quick-curing meats wherein a pickling solution is injected into said meat, the step of adding to said pickling solution a small amount of the antibiotic substance derived from the plant Petalostemum purpureum by treatment with a non-aqueous organic solvent to substantially retard the growth of pathogenic bacteria responsible for food spoilage and poisoning after the said solution is injected into the said meat.

3. In the process of preparing pastries containing fillings subject to spoilage by pathogenic bacteria, the step of adding to the said fillings a small amount of the antibiotic substance derived from the plant Petalostemum purpureum by treatment with a non-aqueous organic solvent to substantially retard the growth of pathogenic bacteria in the said fillings.

4. A meat pickle including a small amount of an antibiotic subst nce de i ed Irom the plant REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 469,850 Chesebrough Mar. 1, 1892 2,084,864 Paddock June 22, 1937 2,098,110 Schertz et al Nov. 2, 1937 2,117,478 Hall May 17, 1938 2,180,750 Urbain Nov. 21, 1939 OTHER REFERENCES Nature, May 13, 1944, vol. 159, page 598, article entitled Antibacterial Substances in Green Plants."

Chemical and Engineering News, September 1945, page 1622, article entitled Penicillin as a Preservative.

The American Womans Cook Book, 1945, by Ruth Berolzheimer, published by Consolidated Book Pub ishe s, C ago. page 4.75. 

1. IN THE PROCESS OF TREATING FOOD PRODUCTS, THE STEP OF ADDING TO A FOOD PRODUCT A SMALL AMOUNT OF AN ANTIBIOTIC SUBSTANCE DERIVED FROM THE PLANT PETALOSTEMUM PURPUREUM BY TREATMENT WITH A NON-AQUEOUS ORGANIC SOLVENT TO PRESERVE SAID FOOD PRODUCT AGAINST PATHOGENIC BACTERIA RESPONSIBLE FOR FOOD POISONING AND SPOILAGE. 